Mamiya RB67 Problems

I checked a Pro S body, film back and revolving adapter. There are 4 pins in the revolving adapter.

3 pins are in the corners of the revolving back. They interface with the film back, to signal the body has been fired, and for the double exposure prevention interlock. 3 pins are needed so that these two functions (body fired and double exp) can function when the film back is positioned in either landscape or portrait orientation.

The fourth pin is in the cocking lever "short" (6cm) side of the revolving adapter. This actuates the red framing guide rods in the viewfinder. I believe this pin does not influence firing of the body.

So have a look at the three pins in the corners. See that they all move in and out smoothly, and return on their own.

To me it sounds like something in the rotating back is interfering.

chassis said:

The rotating adapter has two main function - to rotate (obviously) and to communicate to the film back that the body has fired, through several pins. Problems with rotation generally do not cause failure to fire problems. So it sounds to me like the problem could lie with the pins.

There are three or four pins (don't have my cameras in front of me) that pass through the revolving adapter. Two are in the upper two corners. The other one or two are in the middle of the short (6cm) sides of the adapter.

Be sure the pins move, and return, freely without sticking. A light cleaning with denatured alcohol or naphtha may help. If the pins are bent it may require disassembly to straighten them or to buy a new revolving adapter.

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Thanks for the feedback. Ended up sending to a camera repair guy who told me it was the pins that were bent and everything needed to be straightened and cleaned. Seems like a common issue but not a biggie.